2004 F150 Not Getting Fuel When Warm

Shermanator31660

Petty Officer 3rd Class
Joined
May 15, 2006
Messages
88
I know it's simple but danged if I can figure this out, nor my other 2 "expert" boaters so here I am again! Starting the motor, not problem, head out on lake for a 15 minute run at 30 mph to my fav fishing spot, no problem. Troll around with the kicker for an hour or two, light up the big motor and head out and after about 2 minutes it dies, primer bulb is soft. Pump it up, motor fires right up and away we go, 2 minutes later, dies again, sameo problem. If I leave the wife at the back of the boat and have her continually pumping the bulb, which she really doesn't like doing, the motor runs just fine!
I've checked the screen in the tank, new fuel/water filter, new primer bulb, checked all the hose connections outside motor and under the hood, no leaks. I "deleted the factory fuel bowl and filter under the hood, still made no difference. Something I did notice is that when the motor is off and I get the primer bulb pumped up and hard and then keep pressure on it, the bulb will slowly "bleed down", I don't think it should be doing that but I also can't find any fuel leaks, anywhere. I've never had this problem before, it just started about a month ago, injectors were just all cleaned, motor runs like a top, when it has fuel! I do have my kicker hooked up to the same fuel filter but it runs off a totally separate fitting from the main motor, I even disconnected its line to see if air may have been coming through there but it made no difference. Any ideas?? I don't think the VST filter would be the problem, or a fuel pump, seems to be getting air from somewhere??? Sherm
 

MARV1

Seaman Apprentice
Joined
Jun 27, 2013
Messages
49
New male/female connectors too? Bum o-ring can cause an airleak too, but still hold fuel.
 

Shermanator31660

Petty Officer 3rd Class
Joined
May 15, 2006
Messages
88
No female/male connectors for the F150, its all "hardlined" in, replaced the mickeymouse zap straps on the fuel line with proper hose clamps. Or are you referring to the O Ring on the kicker connections??? Sherm
 

boscoe99

Lieutenant Commander
Joined
Aug 22, 2013
Messages
1,783
If the motor can be made to keep running by your wife pumping the primer ball then I would suspect the mechanical fuel pump. Pumping the primer ball is doing what the fuel pump should be doing on its own.

There is a diaphragm in the fuel pump. If the diaphragm leaks it can cause the pump to be less effective. Fuel can also get into the motor.
 

Shermanator31660

Petty Officer 3rd Class
Joined
May 15, 2006
Messages
88
I thought they were electric fuel pumps? OK, I'll have to recheck the manual, no fuel in the oil as yet........Sherm
 

Shermanator31660

Petty Officer 3rd Class
Joined
May 15, 2006
Messages
88
So there are, what they call, mechanical pumps which they call "lift pumps", taking the fuel into the VST where there is a high pressure electric pump, which then pumps the fuel to the rail. I checked both of the lift pumps with a vacuum pump and visual inspection, both appear to be in working order although one does seem to bleed down a little quicker than the other. No gas going into the motor so the main rubber diaphragm's are OK. I blew a little air through the pump "valves" just in case there was a speck of dirt or something that might keep them from closing. I've also installed a separate "on/off" valve to my kicker so it can be completely shut off when not in use to prevent a possible air leak via the carb on the kicker. Just need a water test now to see where I'm at! I also just finished the re and re on the powerhead to change out my oil pump, what a stupid place to put an oil pump! Sherm
 
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